Tan's use of the word "fragile" to describe the immigrant women's English could be 1) to avoid wincing at the phrase "broken English" (see essay "Mother Tongue); 2) to suggest that the women's grasp of English is as fragile as their hold on their American lives; 3) to emphasize the women's emotional fragility.

My mother could sense that the women of these families also had unspeakable tragedies they had left behind in China and hopes they couldn’t begin to express in their
fragile English.

Although Jing-mei is using this sentence as part of a longer description of how her mother's Kweilin story changes each time it's told, she recognizes how grueling ("characterized by effort to the point of exhaustion") her mother's escape had been.

Months later, after an inspiring Christmastime service at the First Chinese Baptist Church, Auntie An-mei tried to
recoup her loss by saying it truly was more blessed to give than to receive, and my mother agreed, her longtime friend had blessings for at least several lifetimes.

"Oblivious" also means "failing to keep in mind"--both definitions fit here, since Jing-mei is not sure whether Auntie Lin is being thoughtlessly mean or whether she doesn't actually know about Auntie An-mei's greedy family (which is unlikely because the four members of the Joy Luck Club have known each other a long time). Auntie Lin is likely unaware of Auntie An-mei's pain at the moment because she is failing to keep in mind other people while bragging about her own family.

Listening now to Auntie Lin bragging about the virtues of her family in China, I realize that Auntie Lin is
oblivious to Auntie An-mei’s pain.

"Ignorant" also means "uneducated in general; lacking knowledge or sophistication"--this definition does not fit here, because all the daughters have attended college (although not all graduated). The use of the adjective is very specific to their daughters' lack of knowledge about them, their lives, and what's important to them (which are very different than what their daughters have grown up with in America).

They are frightened. In me, they see their own daughters, just as
ignorant, just as unmindful of all the truths and hopes they have brought to America.

So when my brother gave her a sour look, Auntie said our mother was so thoughtless she had fled north in a big hurry, without taking the
dowry furniture from her marriage to my father, without bringing her ten pairs of silver chopsticks, without paying respect to my father’s grave and those of our ancestors.

Above this noise, Popo’s
shrill voice spoke. “Who is this ghost? Not an honored widow. Just a number-three concubine. If you take your daughter, she will become like you. No face. Never able to lift up her head.”

Lindo's childhood home was modest compared to the larger home of her betrothed. It was also "modest" ("marked by simplicity" and "low or inferior in station or quality) because it was on a little hill made up of centuries of mud washed up by a river; this same river ran right through the middle of their lands, and during a summer of heavy rains, made everything unusable and unlivable.

My family lived in a
modest two-story house with a smaller house in the same compound, which was really just two side-by-side rooms for our cook, an everyday servant, and their families.

This room contained tables and chairs carved out of red lacquer, fine pillows embroidered with the Huang family name in the ancient style, and many precious things that gave the look of wealth and old
prestige.

And so the stale heat still remained in the shadows behind the curtains, heating up the acrid smells of my chamber pot, seeping into my pillow,
chafing the back of my neck and puffing up my cheeks, so that I awoke that morning with a restless complaint.

The servants had already packed and loaded a rickshaw with the day’s basic
provisions: a woven hamper filled with zongzi—the sticky rice wrapped in lotus leaves, some filled with roasted ham, some with sweet lotus seeds;

"Bristle" also means "a stiff hair" (which many shrimp have on their legs to help them move) and "rise up as in fear" or "react in an offended or angry manner" (which could also fit since the shrimp have just been plucked from their watery cage and are about to be dipped into sauce and eaten raw).

At last, the day has begun! I raced to the pavilion and found aunts and uncles laughing as they used chopsticks to pick up dancing shrimp, still squirming in their shells, their tiny legs
bristling.